'Chuck': Linda Hamilton is on a need-to-know basis

Based on the season premiere of
"Chuck," it's sort of hard to tell whether
Linda Hamilton is playing for the good guys or the bad guys.

That may be because she herself doesn't know yet.

When she was cast as Chuck's (
Zachary Levi) long-lost mother -- whose absence, we learned in Monday's (Sept. 20) season premiere, was because she was a spy and was captured -- the show's writers told her "absolutely nothing."

"And I still know almost nothing," Hamilton tells
Zap2it during a break in filming the season's seventh episode earlier this week. "I went in and worked the first day, I did three scenes and I'm shooting people, and I'm like, 'Am I the good girl?' And they say, 'We don't know.' 'Am I being held prisoner?' 'We don't know.' So it's a little vague, but it's kind of a fine line to walk. I could go any way, but I can't really tell you."

Hamilton does have her own ideas about Mary Elizabeth Bartowski, though. "She's all business, and everything she says, she believes at that time," she says. "It's not that she's a compulsive liar, but she has to be convincing in every position."

Here's what Hamilton does know: She's having a blast working on "Chuck." "I love the comedy -- I think that's the reason I really wanted to do it," she says. "Because the other stuff, I've done once or twice, the action. But it has such a light touch, and when I watched the show I actually laughed out loud a few times.

"I love the fact that it doesn't take itself too seriously. ... And it's glamorous, it's fun. It's like [going] back to the TV I did in the '80s, only the clothes are better."